Re: Temp. calibration by miked.

> At 15:24 01/05/99 -0500, dave vanhorn wrote: > >>There are (FLUKE) DVMs with a thermocouple adapter plug. Has anyone got > >>any experience with these in this domain (use as refrence during gang > >>calibration of devices for example) ? I know that the FLUKE that has this > >>adapter also has a serial connector, so I can make some computer look > >>after the heater/cooler. > > > >Type J or K thermocouples, very accurate. The meters are compensated for > >their curve. > > for this range don't use thermocouples, they're probably less accurate than > you'd like it (there may be a difference of a couple degrees between > different thermocouples of the same type, according to the standard), and > their intended range is much bigger. Pt100 resistors are better suited for > your range; their accuracy is better and the variation between different > sensors is much smaller. > Our company makes t/c measurement equipment. One of our calibration devices is an Omega Ice Bath (for 0C ref). It consists of petlier junction devices controlled by a microswitch attached to a set of bellows. When ice crystals form on these bellows they contract and turn off the power. No other electronics yet holds within .5 degree Celsius according to the little (and easily breakable) thermometers that come with it. Other points are input from a power supply monitored by a Keithly Nanavoltmeter which is re-certified every year.